What Is Steel Yield Strength?
Steel yield strength is the amount of stress a piece of steel must undergo in order to permanently and measurably deform. The yield strength is most often defined as the point at which a measurable deviation of 0.2 has occurred in the steel. Steel yield strength can be increased using heat treatments or by mixing other materials with the steel to create a steel alloy. Engineers must know the yield strength of the materials they are using in order to ensure that the structures they build will withstand the stresses put on them. Yield strength should not be confused with tensile strength. Tensile strength is the point at which stresses on a metal will cause it to break or snap. By contrast, yield strength is the point at which a metal will undergo plastic deformation. A material is said to have deformed plastically when it bends under stress and cannot return to its original shape after the stress is removed. If the material is able to return to its original shape, this is known as elastic deformation. Elastic deformation can go on for some time before a metal deforms plastically.
Heat treatments can also affect steel yield strength. The purpose of a heat treatment is to either strengthen or soften the metal. Heating and cooling the metal to specified temperatures at controlled speeds changes the crystalline structure of the metal. Crystalline structure is one of the major factors that determines metal strength.
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